Manatees and Pelicans Dying in Indian River Lagoon

At the Indian River Lagoon in Florida, several manatees and pelicans have been found dead, most likely due to the algae blooms that are quickly invading the area. With the deaths of these animals, scientists fear this is the beginning of a devastating ecosystem collapse.

Mar 22, 2013

The Indian River Lagoon has been suffering recently because of microscopic algae blooms, which have caused mass die-offs of seagrass, which shelters aquatic species and is the primary food for manatees. The Orlando Sentinel's Kevin Spear reports manatees began dying in the areas that had the worst seagrass loss last year, but no cause of death has officially been determined.

His report said 80 manatees have been found dead thus far. Brown pelicans also have died in the area, but scientists have not been able to come up with an explanation for their deaths. So far, more than 200 pelican carcasses have been found, Spear reported.

"Manatees eat plants, and pelicans eat fish. The only thing they share is water," Dan Wolf, a state Fish and Wildlife Conservation Commission biologist, told Spear. Investigators believe that manatees are eating gracilaria, a red-colored alga, because of the seagrass shortage and because the dead manatees' stomachs are full of it. Gracilaria isn't known to be toxic, but scientists are trying to find whether some type of toxin is at work.

Wolf said that when the manatees die, it appears to happen quickly, but the pelicans are plagued with parasites for weeks before they perish. The question now is whether the lagoon is transforming from a system where seagrasses and large algae absorb nutrient pollution to a system in which microscopic algae are in control. "Because of what's going on with manatees, we're on alert," Megan Stolen, a scientist at Hubbs-SeaWorld Research Institute, said, according to Spear's article, which said the institute documented five dolphin deaths in February, up from the month's average of 2.3 deaths.